NFS Locking Issue

[Francisco Reyes]

Robert Watson writes:

> can you trigger it using work on just one client against a server, without 
> client<->client interactions?  This makes tracking and reproduction a lot 
> easier

Personally I am experiencing two problems.
1- NFS clients freeze/hang if the server goes away.
We have clients with several mounts so if one of the servers dies then the 
entire operation of the client is put in jeopardy.

This I can reproduce every single time with a 6.X client.. with both a 5.X 
and a 6.X server.

"umount -f" hangs too.


> as multi-client test cases are really tricky! 

The second case only happens under heavy load and restarting nfsd makes it 
go away. Basically 'b' column in vmstat goes high and the performnance of 
the machine falls to the floor.

Going to try 
http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneld 
ebug-deadlocks.html

And reading up on how to debug with DDB. Have another user who volunteered 
to give me some pointers.. so will try that.. so I am able to actually 
produce more helpfull info.